/*
 * TreeRenderer - Draw the major column in a TreeListView
 *
 * Author: Phillip Piper
 * Date: 27/06/2015 
 *
 * Change log:
 * 2016-07-17  JPP  - Added TreeRenderer.UseTriangles and IsShowGlyphs
 * 2015-06-27  JPP  - Split out from TreeListView.cs
 * 
 */

using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.VisualStyles;
using System.Drawing.Drawing2D;

namespace BrightIdeasSoftware {

    public partial class TreeListView {
        /// <summary>
        /// This class handles drawing the tree structure of the primary column.
        /// </summary>
        public class TreeRenderer : HighlightTextRenderer {
            /// <summary>
            /// Create a TreeRenderer
            /// </summary>
            public TreeRenderer() {
                LinePen = new Pen(Color.Blue, 1.0f);
                LinePen.DashStyle = DashStyle.Dot;
            }

            #region Configuration properties

            /// <summary>
            /// Should the renderer draw glyphs at the expansion points?
            /// </summary>
            /// <remarks>The expansion points will still function to expand/collapse even if this is false.</remarks>
            public bool IsShowGlyphs
            {
                get { return isShowGlyphs; }
                set { isShowGlyphs = value; }
            }
            private bool isShowGlyphs = true;

            /// <summary>
            /// Should the renderer draw lines connecting siblings?
            /// </summary>
            public bool IsShowLines
            {
                get { return isShowLines; }
                set { isShowLines = value; }
            }
            private bool isShowLines = true;

            /// <summary>
            /// Return the pen that will be used to draw the lines between branches
            /// </summary>
            public Pen LinePen
            {
                get { return linePen; }
                set { linePen = value; }
            }
            private Pen linePen;

            /// <summary>
            /// Should the renderer draw triangles as the expansion glyphs?
            /// </summary>
            /// <remarks>
            /// This looks best with ShowLines = false
            /// </remarks>
            public bool UseTriangles
            {
                get { return useTriangles; }
                set { useTriangles = value; }
            }
            private bool useTriangles = false;

            #endregion

            /// <summary>
            /// Return the branch that the renderer is currently drawing.
            /// </summary>
            private Branch Branch {
                get {
                    return TreeListView.TreeModel.GetBranch(RowObject);
                }
            }

            /// <summary>
            /// Return the TreeListView for which the renderer is being used.
            /// </summary>
            public TreeListView TreeListView {
                get {
                    return (TreeListView)ListView;
                }
            }

            /// <summary>
            /// How many pixels will be reserved for each level of indentation?
            /// </summary>
            public static int PIXELS_PER_LEVEL = 16 + 1;

            /// <summary>
            /// The real work of drawing the tree is done in this method
            /// </summary>
            /// <param name="g"></param>
            /// <param name="r"></param>
            public override void Render(Graphics g, Rectangle r) {
                DrawBackground(g, r);

                Branch br = Branch;

                Rectangle paddedRectangle = ApplyCellPadding(r);

                Rectangle expandGlyphRectangle = paddedRectangle;
                expandGlyphRectangle.Offset((br.Level - 1) * PIXELS_PER_LEVEL, 0);
                expandGlyphRectangle.Width = PIXELS_PER_LEVEL;
                expandGlyphRectangle.Height = PIXELS_PER_LEVEL;
                expandGlyphRectangle.Y = AlignVertically(paddedRectangle, expandGlyphRectangle);
                int expandGlyphRectangleMidVertical = expandGlyphRectangle.Y + (expandGlyphRectangle.Height/2);

                if (IsShowLines)
                    DrawLines(g, r, LinePen, br, expandGlyphRectangleMidVertical);

                if (br.CanExpand && IsShowGlyphs) 
                    DrawExpansionGlyph(g, expandGlyphRectangle, br.IsExpanded);

                int indent = br.Level * PIXELS_PER_LEVEL;
                paddedRectangle.Offset(indent, 0);
                paddedRectangle.Width -= indent;

                DrawImageAndText(g, paddedRectangle);
            }

            /// <summary>
            /// Draw the expansion indicator
            /// </summary>
            /// <param name="g"></param>
            /// <param name="r"></param>
            /// <param name="isExpanded"></param>
            protected virtual void DrawExpansionGlyph(Graphics g, Rectangle r, bool isExpanded) {
                if (UseStyles) {
                    DrawExpansionGlyphStyled(g, r, isExpanded);
                } else {
                    DrawExpansionGlyphManual(g, r, isExpanded);
                }
            }

            /// <summary>
            /// Gets whether or not we should render using styles
            /// </summary>
            protected virtual bool UseStyles {
                get {
                    return !IsPrinting && Application.RenderWithVisualStyles;
                }
            }

            /// <summary>
            /// Draw the expansion indicator using styles
            /// </summary>
            /// <param name="g"></param>
            /// <param name="r"></param>
            /// <param name="isExpanded"></param>
            protected virtual void DrawExpansionGlyphStyled(Graphics g, Rectangle r, bool isExpanded) {
                if (UseTriangles && IsShowLines) {
                    using (SolidBrush b = new SolidBrush(GetBackgroundColor())) {
                        Rectangle r2 = r;
                        r2.Inflate(-2, -2);
                        g.FillRectangle(b, r2);
                    }
                }

                VisualStyleRenderer renderer = new VisualStyleRenderer(DecideVisualElement(isExpanded));
                renderer.DrawBackground(g, r);
            }

            private VisualStyleElement DecideVisualElement(bool isExpanded) {
                string klass = UseTriangles ? "Explorer::TreeView" : "TREEVIEW";
                int part = UseTriangles && IsExpansionHot ? 4 : 2;
                int state = isExpanded ? 2 : 1;
                return VisualStyleElement.CreateElement(klass, part, state);
            }

            /// <summary>
            /// Is the mouse over a checkbox in this cell?
            /// </summary>
            protected bool IsExpansionHot {
                get { return IsCellHot && ListView.HotCellHitLocation == HitTestLocation.ExpandButton; }
            }

            /// <summary>
            /// Draw the expansion indicator without using styles
            /// </summary>
            /// <param name="g"></param>
            /// <param name="r"></param>
            /// <param name="isExpanded"></param>
            protected virtual void DrawExpansionGlyphManual(Graphics g, Rectangle r, bool isExpanded) {
                int h = 8;
                int w = 8;
                int x = r.X + 4;
                int y = r.Y + (r.Height / 2) - 4;

                g.DrawRectangle(new Pen(SystemBrushes.ControlDark), x, y, w, h);
                g.FillRectangle(Brushes.White, x + 1, y + 1, w - 1, h - 1);
                g.DrawLine(Pens.Black, x + 2, y + 4, x + w - 2, y + 4);

                if (!isExpanded)
                    g.DrawLine(Pens.Black, x + 4, y + 2, x + 4, y + h - 2);
            }

            /// <summary>
            /// Draw the lines of the tree
            /// </summary>
            /// <param name="g"></param>
            /// <param name="r"></param>
            /// <param name="p"></param>
            /// <param name="br"></param>
            /// <param name="glyphMidVertical"> </param>
            protected virtual void DrawLines(Graphics g, Rectangle r, Pen p, Branch br, int glyphMidVertical) {
                Rectangle r2 = r;
                r2.Width = PIXELS_PER_LEVEL;

                // Vertical lines have to start on even points, otherwise the dotted line looks wrong.
                // This is only needed if pen is dotted.
                int top = r2.Top;
                //if (p.DashStyle == DashStyle.Dot && (top & 1) == 0)
                //    top += 1;

                // Draw lines for ancestors
                int midX;
                IList<Branch> ancestors = br.Ancestors;
                foreach (Branch ancestor in ancestors) {
                    if (!ancestor.IsLastChild && !ancestor.IsOnlyBranch) {
                        midX = r2.Left + r2.Width / 2;
                        g.DrawLine(p, midX, top, midX, r2.Bottom);
                    }
                    r2.Offset(PIXELS_PER_LEVEL, 0);
                }

                // Draw lines for this branch
                midX = r2.Left + r2.Width / 2;

                // Horizontal line first
                g.DrawLine(p, midX, glyphMidVertical, r2.Right, glyphMidVertical);

                // Vertical line second
                if (br.IsFirstBranch) {
                    if (!br.IsLastChild && !br.IsOnlyBranch)
                        g.DrawLine(p, midX, glyphMidVertical, midX, r2.Bottom);
                } else {
                    if (br.IsLastChild)
                        g.DrawLine(p, midX, top, midX, glyphMidVertical);
                    else
                        g.DrawLine(p, midX, top, midX, r2.Bottom);
                }
            }

            /// <summary>
            /// Do the hit test
            /// </summary>
            /// <param name="g"></param>
            /// <param name="hti"></param>
            /// <param name="x"></param>
            /// <param name="y"></param>
            protected override void HandleHitTest(Graphics g, OlvListViewHitTestInfo hti, int x, int y) {
                Branch br = Branch;

                Rectangle r = ApplyCellPadding(Bounds);
                if (br.CanExpand) {
                    r.Offset((br.Level - 1) * PIXELS_PER_LEVEL, 0);
                    r.Width = PIXELS_PER_LEVEL;
                    if (r.Contains(x, y)) {
                        hti.HitTestLocation = HitTestLocation.ExpandButton;
                        return;
                    }
                }

                r = Bounds;
                int indent = br.Level * PIXELS_PER_LEVEL;
                r.X += indent;
                r.Width -= indent;

                // Ignore events in the indent zone
                if (x < r.Left) {
                    hti.HitTestLocation = HitTestLocation.Nothing;
                } else {
                    StandardHitTest(g, hti, r, x, y);
                }
            }

            /// <summary>
            /// Calculate the edit rect
            /// </summary>
            /// <param name="g"></param>
            /// <param name="cellBounds"></param>
            /// <param name="item"></param>
            /// <param name="subItemIndex"></param>
            /// <param name="preferredSize"> </param>
            /// <returns></returns>
            protected override Rectangle HandleGetEditRectangle(Graphics g, Rectangle cellBounds, OLVListItem item, int subItemIndex, Size preferredSize) {
                return StandardGetEditRectangle(g, cellBounds, preferredSize);
            }
        }
    }
}